Celiac disease is an immune reaction to eating gluten, a protein found in wheat, barley and rye.

If you have celiac disease, eating gluten triggers an immune response in your small intestine. Over time, this reaction produces inflammation that damages the small intestine's lining and prevents absorption of some nutrients (malabsorption).

In children, malabsorption can affect growth and development. The intestinal irritation can cause stomach pain, especially after eating.

There's no cure for celiac disease — but following a strict gluten-free diet can help manage symptoms and promote intestinal healing

The signs and symptoms of celiac disease can vary greatly.

Although the classic signs are diarrhea and weight loss, most people with celiac disease experience few or no digestive signs or symptoms. Only about one-third of people diagnosed with celiac disease experience diarrhea, and about half have weight loss.

Twenty percent of people with celiac disease have constipation, and 10 percent are obese.

In addition to digestive problems, other signs and symptoms of celiac disease include:

Anemia, usually resulting from iron deficiency

Loss of bone density (osteoporosis) or softening of bone (osteomalacia)

Itchy, blistery skin rash (dermatitis herpetiformis)

Damage to dental enamel

Headaches and fatigue

Nervous system injury, including numbness and tingling in the feet and hands, and possible problems with balance

Joint pain

Reduced functioning of the spleen (hyposplenism)

Acid reflux and heartburn

Children

As many as 75 percent of children with celiac disease are overweight or obese. Digestive signs and symptoms are experienced by 20 to 30 percent of children with the condition although the precise signs and symptoms differ by age.

Dermatitis herpetiformis

Dermatitis herpetiformis is an itchy, blistering skin disease that stems from intestinal gluten intolerance. The rash usually occurs on the elbows, knees, torso, scalp and buttocks.

Dermatitis herpetiformis is often associated with changes to the lining of the small intestine identical to that of celiac disease, but the disease may not produce noticeable digestive symptoms.

Dermatitis herpetiformis is treated with a gluten-free diet and medication to control the rash.

When to see a doctor

Consult your doctor if you have diarrhea or digestive discomfort that lasts for more than two weeks.Consult your child's doctor if he or she is pale, irritable or failing to grow or has a potbelly and foul-smelling, bulky stools.

Be sure to consult your doctor before trying a gluten-free diet. If you stop eating gluten before you're tested for celiac disease, you may change the test results.

Celiac disease tends to run in families. If someone in your family has the condition, ask your doctor if you should be tested. Also ask your doctor about testing if you or someone in your family has a risk factor for celiac disease, such as type 1 diabetes.

The precise cause of celiac disease isn't known.

When the body's immune system overreacts to gluten in food, the immune reaction damages the tiny, hair-like projections (villi) that line the small intestine. Villi absorb vitamins, minerals and other nutrients from the food you eat. Normally, villi resemble the deep pile of a plush carpet, on a microscopic scale. The damage resulting from celiac disease makes the inner surface of the small intestine appear more like a tile floor. As a result your body is unable to absorb nutrients necessary for health and growth.

A study done by Mayo Clinic and the National Institutes of Health estimates that about 1 in 141 people in the U.S. have celiac disease, although the disease often goes undiagnosed. Celiac disease is most common in Caucasians.

Some gene changes (mutations) appear to increase the risk of developing the disease. But having those gene mutations doesn't mean you'll get celiac disease — meaning other factors must be involved.

Sometimes celiac disease is triggered — or becomes active for the first time — after surgery, pregnancy, childbirth, viral infection or severe emotional stress.

Celiac disease can affect anyone. However, it tends to be more common in people who have:

A family member with celiac disease or dermatitis herpetiformis

Type 1 diabetes

Down syndrome or Turner syndrome

Autoimmune thyroid disease

Sjogren's syndrome

Microscopic colitis (lymphocytic or collagenous colitis)

Untreated, celiac disease can cause:

Malnutrition. The damage to your small intestine means it can't absorb enough nutrients. Malnutrition can lead to anemia and weight loss. In children, malnutrition can cause stunted growth and delayed development.

Loss of calcium and bone density. Malabsorption of calcium and vitamin D may lead to a softening of the bone (osteomalacia or rickets) in children and a loss of bone density (osteoporosis) in adults.

Infertility and miscarriage. Malabsorption of calcium and vitamin D can contribute to reproductive issues.

Lactose intolerance. Damage to your small intestine may cause you to experience abdominal pain and diarrhea after eating lactose-containing dairy products, even though they don't contain gluten. Once your intestine has healed, you may be able to tolerate dairy products again. However, some people continue to experience lactose intolerance despite successful management of celiac disease.

Cancer. People with celiac disease who don't maintain a gluten-free diet have a greater risk of developing several forms of cancer, including intestinal lymphoma and small bowel cancer.

Nonresponsive celiac disease

As many as 15 percent of people with celiac disease may not have or be able to maintain a good response to the gluten-free diet. This condition, known as nonresponsive celiac disease, is often due to contamination of the diet with gluten.

A Mayo Clinic study found that people with nonresponsive celiac disease often have additional conditions, such as bacteria in the small intestine (bacterial overgrowth), colitis, poor pancreas function or irritable bowel syndrome.

Refractory celiac disease

In rare instances, the intestinal injury of celiac disease continues even though you follow a strict gluten-free diet. This is known as refractory celiac disease.

If you continue to experience signs and symptoms despite following a gluten-free diet for six months to one year, your doctor may recommend further testing to monitor the celiac disease and look for other explanations for your symptoms. Your doctor may recommend treatment with a steroid to reduce intestinal inflammation, or a medication that suppresses your immune system.

You may be referred to a doctor who treats digestive diseases (gastroenterologist).

Here's some information to help you prepare for your appointment and know what to expect from your doctor.

What you can do

Continue eating a normal diet. If you stop eating gluten before you're tested for celiac disease, you may change the test results.

Write down your symptoms, including when they started and how they may have changed over time.

Write down key personal information, including any major stresses or recent life changes.

Make a list of all medications, vitamins or supplements that you're taking.

Write down questions to ask your doctor.

Questions to ask your doctor

Some basic questions to ask your doctor include:

What's the most likely cause of my symptoms?

Is my condition temporary or long term?

What kinds of tests do I need?

What treatments can help?

Are there any dietary restrictions that I need to follow?

How will I learn which foods contain gluten? Should I see a dietitian?

If I have celiac disease, will you also test for other conditions such as vitamin or mineral deficiencies, osteoporosis or diabetes?

Don't hesitate to ask other questions during your appointment.

What to expect from your doctor

Be ready to answer questions your doctor may ask:

When did you first begin experiencing symptoms, and how severe are they?

Have your symptoms been continuous or occasional?

What, if anything, seems to improve your symptoms?

What, if anything, seems to worsen your symptoms?

What medications and pain relievers do you take?

Does anyone in your family have celiac disease?

Do you or does anyone in your family have an autoimmune disorder?

Have you had any blistering or itchy skin rashes with your symptoms?

Have you ever been diagnosed with anemia or osteoporosis?

Tests and procedures used to diagnose celiac disease include:

Blood tests. Elevated levels of certain substances in your blood (antibodies) indicate an immune reaction to gluten. These tests detect celiac disease even if you have only mild symptoms or none at all.

Endoscopy. If your blood tests indicate celiac disease, your doctor may order an endoscopy to view your small intestine and to take a small tissue sample (biopsy) to analyze for damage to the villi.

Capsule endoscopy. Capsule endoscopy uses a tiny wireless camera to take pictures of your entire small intestine. The camera sits inside a vitamin-sized capsule, which you swallow. As the capsule travels through your digestive tract, the camera takes thousands of pictures that are transmitted to a recorder.

It's important to be tested for celiac disease before trying a gluten-free diet. Eliminating gluten from your diet may change the results of blood tests so that they appear to be normal.

A gluten-free diet is essential, and the only treatment for managing celiac disease. In addition to wheat, foods that contain gluten include:

Barley

Bulgur

Durum

Farina

Graham flour

Malt

Rye

Semolina

Spelt (a form of wheat)

Triticale

Your doctor may refer you to a dietitian, who can help you plan a healthy gluten-free diet.

Once gluten is removed from the diet, inflammation in the small intestine generally begins to lessen — usually within several weeks, though you may start to feel better in just a few days. Complete healing and regrowth of the villi may take several months to several years. Healing in the small intestine tends to occur more quickly in children than adults.

If you accidentally eat a product that contains gluten, you may experience abdominal pain and diarrhea. Some people experience no signs or symptoms after eating gluten, but this doesn't mean it's not harmful. Even trace amounts of gluten in your diet can be damaging, whether or not they cause signs or symptoms.

Vitamin and mineral supplements

If your nutritional deficiencies are severe, your doctor or dietitian may recommend taking vitamin and mineral supplements. You may need to supplement your levels of:

Calcium

Folate

Iron

Vitamin B-12

Vitamin D

Vitamin K

Zinc

Vitamin supplements are usually taken in pill form. If your digestive tract has trouble absorbing vitamins, your doctor may give them by injection.

Medications to control intestinal inflammation

If your small intestine is severely damaged, your doctor may recommend steroids to control inflammation. Steroids can ease severe signs and symptoms of celiac disease while the intestine heals.

Dermatitis herpetiformis

If you have this itchy, blistering skin rash that sometimes accompanies celiac disease, your doctor may recommend a skin medication (dapsone) along with the gluten-free diet.

If you've been diagnosed with celiac disease, you'll need to avoid all foods that contain gluten. Ask your doctor for a referral to a dietitian, who can help you plan a healthy gluten-free diet.

Here's an overview of foods that contain gluten and gluten-free foods that are safe to eat.

Always avoid

Avoid food and drinks containing:

Barley

Bulgur

Durum

Farina

Graham flour

Malt

Rye

Semolina

Spelt (a form of wheat)

Triticale

Wheat

Read labels

Packaged foods should be avoided unless they're labeled as gluten-free or have no gluten-containing ingredients. In addition to cereals, pastas and baked goods — such as breads, cakes, pies and cookies — other packaged foods that may contain gluten include:

Beer

Candies

Gravies

Imitation meats or seafood

Processed luncheon meats

Salad dressings and sauces, including soy sauce

Self-basting poultry

Soups

Certain grains, such as oats, can be contaminated with wheat during growing and processing. It's not clear whether oats are harmful for most people with celiac disease, but doctors generally recommend avoiding oats unless they are specifically labeled gluten-free. Occasionally, even pure oats can be a problem for people with celiac disease.

Fortunately for bread and pasta lovers with celiac disease, an increasing number of gluten-free products are available. If you can't find any at your local bakery or grocery store, check online. There are gluten-free substitutes for many gluten-containing foods.

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